Nautilus Increases Mineral Resources

A successful exploration drilling campaign conducted at Nautilus Minerals Inc.’s tenements in the Bismarck Sea of Papua New Guinea has enabled the company to increase the resource estimate at its Solwara 1 project and to declare a maiden inferred resource at the nearby Solwara 12 deposit.

The key features of the resource update, prepared by independent consultant Golder Associates Pty. Ltd. in accordance with National Instrument NI 43-101, and stated at a copper-equivalent cut-off grade of 2.6 per cent, are as follows:

The company’s total indicated resources have increased 18 per cent to 1.03

million tonnes.

Total inferred resources have risen 36 per cent to 1.8 million tonnes.

Contained copper in indicated resource at Solwara 1 has increased 25 per cent to

approximately 74,000 tonnes.

Contained copper in inferred resource at Solwara 1 has increased 28 per cent to

approximately 125,000 tonnes. Contained gold in indicated resource at Solwara 1 has increased 23 per cent to

approximately 166,000 ounces.

Contained gold in inferred resource at Solwara 1 has increased 5 per cent to

approximately 317,000 ounces.

A maiden inferred resource has been declared at Solwara 12, 25 kilometres to the

northwest of Solwara 1, of 230,000 tonnes, grading 7.3 per cent copper and 3.6

grams per tonne gold.

• The company’s total indicated resources have increased 18 per cent to 1.03

million tonnes.

• Total inferred resources have risen 36 per cent to 1.8 million tonnes.
• Contained copper in indicated resource at Solwara 1 has increased 25 per cent to

approximately 74,000 tonnes.

• Contained copper in inferred resource at Solwara 1 has increased 28 per cent to

approximately 125,000 tonnes.

• Contained gold in indicated resource at Solwara 1 has increased 23 per cent to

approximately 166,000 ounces.

• Contained gold in inferred resource at Solwara 1 has increased 5 per cent to

approximately 317,000 ounces.

• A maiden inferred resource has been declared at Solwara 12, 25 kilometres to the

northwest of Solwara 1, of 230,000 tonnes, grading 7.3 per cent copper and 3.6

grams per tonne gold.

The increases in contained metal within the resource are a result of additional tonnes and, importantly, higher grades, due to successful resource drilling which identified further high-grade ore zones. The increase in tonnes was also partly due to a reduction in the cut-off grade from 4 per cent copper, used in the prior 2008 resource statement, to a copper equivalent cut-off grade of 2.6 per cent in the 2011 resource, following refinements in the project design.

Nautilus Minerals president and chief executive officer Steve Rogers said the notable increase in the company’s resource base demonstrated the success of the exploration campaign, extending the life of the Solwara 1 project and delivering an improved knowledge of the Bismarck Sea geology.

“Importantly, the declaration of a maiden resource at Solwara 12 begins the process of building a pipeline of projects for Nautilus in the region and confirms the prospectivity of the Bismarck Sea, where we have identified another 16 prospects for further evaluation.

“Nautilus will attempt to build on this base in the coming year through ongoing exploration activities in PNG and elsewhere in the western Pacific,” Mr. Rogers said.

“Nautilus will be undertaking important work including the use of multibeam sonar and seismic exploration tools in the Bismarck Sea over the coming months to assist in identifying targets for drilling, scheduled to be conducted in the second half of next year.

“As part of that program we will be testing for additional lenses of high-grade material in the vicinity of Solwara 1, while the limits of Solwara 12 have yet to be fully identified,” he said.

Nautilus Minerals resource estimates for 2008 and 2011, as prepared by Golder Associates, are tabulated.

SOLWARA 1

Tonnes Cu Au Ag Zn Contained Contained

Class (kt) (%) (g/t) (g/t) (%) Cu (t) Au (Koz)

2008, Indicated 870 6.8 4.8 23 0.4 59,160 134.3

at 4% Cu

cut-off Inferred 1300 7.5 7.2 37 0.8 97,500 300.9

2011, Indicated 910 7.7 5.4 24 0.4 70,070 158.0

at 4% Cu

cut-off Inferred 1365 8.8 6.9 36 0.9 120,120 302.8

2011, Indicated 1030 7.2 5.0 23 0.4 74,160 165.6

at 2.6% Cu

equivalent

cut-off Inferred 1540 8.1 6.4 34 0.9 124,740 316.9

SOLWARA 12 — 2011

(at 2.6-per-cent-coppper-equivalent cut-off)

Tonnes Cu Au Ag Zn Contained Contained

Class (kt) (%) (g/t) (g/t) (%) Cu (t) Au (Koz)

Inferred 230 7.3 3.6 56 3.6 16,790 26.6

Resource estimates were prepared by Ian Lipton (BSc) (honours), FAusIMM, principal geologist, Golder Associates, Toowong, Queensland, Australia, who fulfills the requirements to be a qualified person for the purposes of NI 43-101 . Rounding may result in errors in reproducing the totals from the individual components shown in the table. Copper equivalent (CuEq) equals 0.915 times copper plus 0.254 times gold plus 0.00598 times silver.

The 2011 resource is estimated based on 276 drill holes and a cut-off grade of 2.6 per cent CuEq at an effective date of Nov. 25, 2011. The CuEq grade calculation includes allowances for metallurgical recovery (91.5 per cent for Cu, 45 per cent for Au and 50 per cent for Ag) and smelter payable metal. Metal prices used for the 2011 CuEq cut-off grade calculation are $3.90 (U.S.) per pound Cu, $1,510 (U.S.) per ounce Au and $32 (U.S.) per ounce Ag. Density was assigned to each geological zone based on 890 measurements taken from core specimens. Solwara 1 and 12 were estimated using ordinary kriging, with the exception of the Solwara 1 North zone, which was estimated using inverse-distance weighting. Details of the resource estimation process will be provided in Golder’s NI 43-101-compliant report, which will be available on SEDAR shortly.

The updated resource estimate was prepared following a 1,475-metre, 99-hole diamond drilling campaign conducted in the Bismarck Sea from November, 2010, until May, 2011.

Drilling was focused within the area of the mining lease (ML154) granted to Nautilus earlier this year, which contains the Solwara 1 deposit. A total of 71 holes was drilled in ML154, for 1,147 metres. The remainder of the drilling was conducted in exploration lease 1374, which hosts Solwara 12.